The present invention relates to a honeycomb structure-forming die and a method for manufacturing the honeycomb structure-forming die. More preferably, the present invention relates to a honeycomb structure-forming die which realize high formability and where two plate-shaped members constituting the die substrate are hardly peeled from each other and a manufacturing method thereof.
As a method for manufacturing a ceramic honeycomb structure, heretofore, there has widely employed a method by extrusion-forming using a honeycomb structure-forming die (hereinbelow sometimes referred to simply as a “die”) provided with a die substrate having back holes for introducing a raw forming material (kneaded clay) and slits having a lattice shape or the like and communicating with the back holes. Generally, the die is provided with lattice-shaped slits having a width corresponding to the partition wall thickness of the honeycomb structure on a face on one side of the die substrate and back holes each having a large area and communicating with the slits on a surface on the opposite side (surface on the other side). Generally, the back holes are disposed so as to correspond with the position where slits in a lattice shape or the like cross each other, and the back holes and the slits communicate with each other inside the die substrate. Therefore, a raw forming material such as a ceramic raw material introduced from the back holes moves from the back holes having a relatively large inner diameter to the narrow slits and extruded from opening portions of the slits as a honeycomb structured formed article (honeycomb formed article).
As the die substrate constituting such a honeycomb structure-forming die, there is employed, for example, a die substrate of a plate-shaped member constituted of one kind of alloy such as a stainless alloy or a carbide alloy or a die substrate obtained by laminating and bonding a plate-shaped member for forming slits and a plate-shaped member for forming back holes together (see, e.g., JP-A-2000-326318 and JP-A-2003-285308).
For the plate-shaped member for forming the back holes, there has been proposed a manufacturing method for a honeycomb structure-forming die, the method includes a step for forming grooves corresponding with a shape of the slits so that the slits can suitably be processed after bonding (see, e.g., JP-A-2006-51682)
As such a method for manufacturing a honeycomb structure-forming die, there has been disclosed a method where, upon bonding the two plate-shaped members with a bonding material (brazing material), they are heated at a temperature where the bonding material melts or higher with reducing pressure in the heating atmosphere to a pressure lower than vapor pressure of the brazing material to obtain the die substrate (JP-A-2007-181976). According to such a manufacturing method, the amount of residual bonding material in the die substrate can be reduced.
However, in the case that grooves are formed in the plate-shaped member for forming back holes as in JP-A-2006-51682 and JP-A-2007-181976, there arises a problem that the bonded two plate-shaped members are easily peeled from each other to easily cause defective bonding.